FORUM: Remote testing for psychological and physiological acoustics.

Acoustics research involving human participants typically takes place in specialized laboratory settings. Listening studies, for example, may present controlled sounds using calibrated transducers in sound-attenuating or anechoic chambers. In contrast, remote testing takes place outside of the laboratory in everyday settings (e.g., participants' homes). Remote testing could provide greater access to participants, larger sample sizes, and opportunities to characterize performance in typical listening environments at the cost of reduced control of environmental conditions, less precise calibration, and inconsistency in attentional state and/or response behaviors from relatively smaller sample sizes and unintuitive experimental tasks. The Acoustical Society of America Technical Committee on Psychological and Physiological Acoustics launched the Task Force on Remote Testing (https://tcppasa.org/remotetesting/) in May 2020 with goals of surveying approaches and platforms available to support remote testing and identifying challenges and considerations for prospective investigators. The results of this task force survey were made available online in the form of a set of Wiki pages and summarized in this report. This report outlines the state-of-the-art of remote testing in auditory-related research as of August 2021, which is based on the Wiki and a literature search of papers published in this area since 2020, and provides three case studies to demonstrate feasibility during practice.

Exponential spectro-temporal modulation generation.

Traditionally, real-time generation of spectro-temporally modulated noise has been performed on a linear amplitude scale, partially due to computational constraints. Experiments often require modulation that is sinusoidal on a logarithmic amplitude scale as a result of the many perceptual and physiological measures which scale linearly with exponential changes in the signal magnitude. A method is presented for computing exponential spectro-temporal modulation, showing that it can be expressed analytically as a sum over linearly offset sidebands with component amplitudes equal to the values of the modified Bessel function of the first kind. This approach greatly improves the efficiency and precision of stimulus generation over current methods, facilitating real-time generation for a broad range of carrier and envelope signals.

Temporal integration of monaural and dichotic frequency modulation.

Frequency modulation (FM) detection at low modulation frequencies is commonly used as an index of temporal fine-structure processing. The present study evaluated the rate of improvement in monaural and dichotic FM across a range of test parameters. In experiment I, dichotic and monaural FM detection was measured as a function of duration and modulator starting phase. Dichotic FM thresholds were lower than monaural FM thresholds and the modulator starting phase had no effect on detection. Experiment II measured monaural FM detection for signals that differed in modulation rate and duration such that the improvement with duration in seconds (carrier) or cycles (modulator) was compared. Monaural FM detection improved monotonically with the number of modulation cycles, suggesting that the modulator is extracted prior to detection. Experiment III measured dichotic FM detection for shorter signal durations to test the hypothesis that dichotic FM relies primarily on the signal onset. The rate of improvement decreased as duration increased, which is consistent with the use of primarily onset cues for the detection of dichotic FM. These results establish that improvement with duration occurs as a function of the modulation cycles at a rate consistent with the independent-samples model for monaural FM, but later cycles contribute less to detection in dichotic FM.

Portable Automated Rapid Testing (PART) for auditory assessment: Validation in a young adult normal-hearing population.

This study aims to determine the degree to which Portable Automated Rapid Testing (PART), a freely available program running on a tablet computer, is capable of reproducing standard laboratory results. Undergraduate students were assigned to one of three within-subject conditions that examined repeatability of performance on a battery of psychoacoustical tests of temporal fine structure processing, spectro-temporal amplitude modulation, and targets in competition. The repeatability condition examined test/retest with the same system, the headphones condition examined the effects of varying headphones (passive and active noise-attenuating), and the noise condition examined repeatability in the presence of recorded cafeteria noise. In general, performance on the test battery showed high repeatability, even across manipulated conditions, and was similar to that reported in the literature. These data serve as validation that suprathreshold psychoacoustical tests can be made accessible to run on consumer-grade hardware and perform in less controlled settings. This dataset also provides a distribution of thresholds that can be used as a normative baseline against which auditory dysfunction can be identified in future work.

Development of the Continuous Number Identification Test (CNIT): feasibility of dynamic assessment of speech intelligibility.

Objective: The present study was motivated by a need for a speech intelligibility test capable of indexing dynamic changes in the environment and adaptive processing in hearing aids. The Continuous Number Identification Test (CNIT) was developed to meet these aims.Design: From one location in the free field, speech was presented in noise (∼2 words/s) with a 100-ms inter-word interval. On average, every fourth word was a target digit and all other words were monosyllabic words. Non-numeric words had a fixed presentation level such that the dominant signal-to-noise-ratio (SNR) was held at +6 dB SNR relative to background maskers. To prevent ceiling effects, however, targets were presented at a user-specific SNR, determined by an initial adaptive-tracking procedure that estimated the 79.4% speech reception threshold.Study sample: Ten normal-hearing listeners participated.Results: The CNIT showed comparable psychometric qualities of other established speech tests for long time scales (Exp. 1). Target-location changes did not affect performance on the CNIT (Exp. 2), but the test did show high temporal resolution in assessing sudden changes to SNR (Exp. 3).Conclusions: The CNIT is highly customisable, and the initial experiments tested feasibility of its primary features which set it apart from currently available speech-in-noise tests.

Distribution of spectral modulation transfer functions in a young, normal-hearing population.

Spectral modulation transfer functions (SMTFs) were measured in 49 young (18-35 years of age) normal-hearing listeners. Noise carriers spanned six octaves from 200 to 12 800 Hz. Sinusoidal (on a log-amplitude scale) spectral modulation with random starting phase was superimposed on the carrier at spectral modulation frequencies of 0.25, 0.5, 1.0, 2.0, 4.0, and 8.0 cycles/octave. Modulation detection thresholds (in dB) yielded SMTFs that were bandpass in nature, consistent with previous investigations reporting data for only a few subjects. Thresholds were notably consistent across subjects despite minimal practice. Population statistics are reported that may serve as reference data for future studies.

Over-the-Counter Hearing Aids Challenge the Core Values of Traditional Audiology.

PURPOSE: Regulatory changes in the United States introduced over-the-counter (OTC) hearing aids with the goal of increasing the accessibility and affordability of hearing health care. It is critical to understand the values inherent to hearing health care systems to evaluate their effectiveness in serving people with hearing difficulty. In this study, we evaluated the relative importance of values across service delivery models and the extent to which the introduction of OTC hearing aids represents a values shift relative to traditional audiology. METHOD: We performed a qualitative content analysis of two document categories: critique documents that motivated the creation of OTC hearing aids and regulatory documents that defined OTC hearing aids. Team members coded portions of text for the values they expressed. In total, 29,235 words were coded across 72 pages in four documents. Rank-order analyses were performed to determine the prioritization of values within each category of documents and subsequently compare values between OTC and traditional audiology documents analyzed in a previous study. RESULTS: Critique and regulatory documents both prioritized values related to reducing barriers to hearing aid access and use, but the lack of a significant correlation in the rank order of values in these documents was evidence of inconsistency between the motivation and implementation of OTC hearing aids. Differences in the rank order of values in the OTC documents compared to traditional audiology were consistent with a values shift. CONCLUSIONS: The introduction of OTC as a solution to low hearing aid use represents a values shift, challenging the values of traditional audiology. This research demonstrates a need to establish the values of hearing health care service delivery through a consensus of stakeholders, including individuals from diverse backgrounds underserved by the traditional model.

Core Values in the Traditional Provision of Hearing Health Care.

PURPOSE: Untreated hearing loss is a significant public health issue affecting the quality of life of millions of Americans. Barriers to treatment invite novel and innovation solutions, but as these solutions create new treatment delivery models, they also may-purposefully or accidentally-challenge the values of the field. METHOD: Value-sensitive design methodology is used in this study to identify the values in current hearing health care service delivery. We performed qualitative content analysis of questionnaires, clinical practice guidelines, and professional ethics documents that represent the intended and enacted values in audiology. RESULTS: The result is a comprehensive list of values that can be used as a structured codebook for systematic textual analysis of materials representing current best practices in the provision of hearing health care services. A secondary result is an analysis of the relative importance of values in audiology, inferred from the frequency of references to each value. CONCLUSIONS: Subjective benefit, professional duties, and self-efficacy were the core values identified in the current provision of audiologic care, and these values should be central to considerations for new hearing health care models and technologies.

Senior Care Pharmacists, Audiologists, and Otologists: Improving Hearing Health for Older Patients Through Interprofessional Collaboration.

The purpose of this manuscript is to provide pharmacists with education on hearing loss that colleagues in audiology believe is most critical for pharmacists. As well as highlighting insightful interventions pharmacists can make in collaboration with hearing professionals, such as audiologists, otolaryngologists, and otologists, to improve patient care. This project was initiated by professional students at the University of Maryland in both Baltimore and College Park campuses, after completing the interprofessional elective course IPE Care in Geriatrics. Upon completion of the course, the authors performed an extensive literature search and reviewed publications pertaining to pharmacy, audiology, and their integration.Hearing loss can have a significant impact on a patient's quality of life. Older people are at an increased risk for experiencing hearing impairment, but often do not seek help from health care providers. Collaboration between audiologists, otolaryngologists, and pharmacists has the potential to improve patients' access to hearing health and break barriers for patients. Important interventions that pharmacists can make to better serve their patients with hearing loss include screening, enhancing communication, and hearing aid assistance. This article also provides guidance on identifying patients who would be candidates for over-the-counter hearing aids and patients who should be referred to a hearing professional. This skill will become increasingly relevant with the emergence of over-the-counter hearing aids.

A three-step pattern in audiometric thresholds.

Use of the audiogram as the gold standard index of hearing ability amplifies the consequences of error in threshold measurement. A Markov chain model of the audiometric procedure revealed a three-step pattern in the stimuli presented each trial. Monte Carlo simulations were used to generate threshold estimates for a simple listener model. Thresholds sorted by trial had a mean bias consistent with model predictions. An alternate scoring method is proposed that uses equal sampling of Markov states. The resulting threshold targets a specific probability of detection and has no systematic bias as a function of trial.

A Comparison of Behavioral Methods for Indexing the Auditory Processing of Temporal Fine Structure Cues.

Purpose Growing evidence supports the inclusion of perceptual tests that quantify the processing of temporal fine structure (TFS) in clinical hearing assessment. Many tasks have been used to evaluate TFS in the laboratory that vary greatly in the stimuli used and whether the judgments require monaural or binaural comparisons of TFS. The purpose of this study was to compare laboratory measures of TFS for inclusion in a battery of suprathreshold auditory tests. A subset of available TFS tasks were selected on the basis of potential clinical utility and were evaluated using metrics that focus on characteristics important for clinical use. Method TFS measures were implemented in replication of studies that demonstrated clinical utility. Monaural, diotic, and dichotic measures were evaluated in 11 young listeners with normal hearing. Measures included frequency modulation (FM) tasks, harmonic frequency shift detection, interaural phase difference (TFS-low frequency), interaural time difference (ITD), monaural gap duration discrimination, and tone detection in noise with and without a difference in interaural phase (N0S0, N0Sπ). Data were compared with published results and evaluated with metrics of consistency and efficiency. Results Thresholds obtained were consistent with published data. There was no evidence of predictive relationships among the measures consistent with a homogenous group. The most stable tasks across repeated testing were TFS-low frequency, diotic and dichotic FM, and N0Sπ. Monaural and diotic FM had the lowest normalized variance and were the most efficient accounting for differences in total test duration, followed by ITD. Conclusions Despite a long stimulus duration, FM tasks dominated comparisons of consistency and efficiency. Small differences separated the dichotic tasks FM, ITD, and N0Sπ. Future comparisons following procedural optimization of the tasks will evaluate clinical efficiency in populations with impairment.

Development and validation of Portable Automated Rapid Testing (PART) measures for auditory research.

The current state of consumer-grade electronics means that researchers, clinicians, students, and members of the general public across the globe can create high-quality auditory stimuli using tablet computers, built-in sound hardware, and calibrated consumer-grade headphones. Our laboratories have created a free application that supports this work: PART (Portable Automated Rapid Testing). PART has implemented a range of psychoacoustical tasks including: spatial release from speech-on-speech masking, binaural sensitivity, gap discrimination, temporal modulation, spectral modulation, and spectrotemporal modulation (STM). Here, data from the spatial release and STM tasks are presented. Data were collected across the globe on tablet computers using applications available for free download, built-in sound hardware, and calibrated consumer-grade headphones. Spatial release results were as good or better than those obtained with standard laboratory methods. Spectrotemporal modulation thresholds were obtained rapidly and, for younger normal hearing listeners, were also as good or better than those in the literature. For older hearing impaired listeners, rapid testing resulted in similar thresholds to those reported in the literature. Listeners at five different testing sites produced very similar STM thresholds, despite a variety of testing conditions and calibration routines. Download Spatial Release, PART, and Listen: An Auditory Training Experience for free at https://bgc.ucr.edu/games/.

Auditory and Cognitive Factors Associated with Speech-in-Noise Complaints following Mild Traumatic Brain Injury.

BACKGROUND: Auditory complaints following mild traumatic brain injury (MTBI) are common, but few studies have addressed the role of auditory temporal processing in speech recognition complaints. PURPOSE: In this study, deficits understanding speech in a background of speech noise following MTBI were evaluated with the goal of comparing the relative contributions of auditory and nonauditory factors. RESEARCH DESIGN: A matched-groups design was used in which a group of listeners with a history of MTBI were compared to a group matched in age and pure-tone thresholds, as well as a control group of young listeners with normal hearing (YNH). STUDY SAMPLE: Of the 33 listeners who participated in the study, 13 were included in the MTBI group (mean age = 46.7 yr), 11 in the Matched group (mean age = 49 yr), and 9 in the YNH group (mean age = 20.8 yr). DATA COLLECTION AND ANALYSIS: Speech-in-noise deficits were evaluated using subjective measures as well as monaural word (Words-in-Noise test) and sentence (Quick Speech-in-Noise test) tasks, and a binaural spatial release task. Performance on these measures was compared to psychophysical tasks that evaluate monaural and binaural temporal fine-structure tasks and spectral resolution. Cognitive measures of attention, processing speed, and working memory were evaluated as possible causes of differences between MTBI and Matched groups that might contribute to speech-in-noise perception deficits. RESULTS: A high proportion of listeners in the MTBI group reported difficulty understanding speech in noise (84%) compared to the Matched group (9.1%), and listeners who reported difficulty were more likely to have abnormal results on objective measures of speech in noise. No significant group differences were found between the MTBI and Matched listeners on any of the measures reported, but the number of abnormal tests differed across groups. Regression analysis revealed that a combination of auditory and auditory processing factors contributed to monaural speech-in-noise scores, but the benefit of spatial separation was related to a combination of working memory and peripheral auditory factors across all listeners in the study. CONCLUSIONS: The results of this study are consistent with previous findings that a subset of listeners with MTBI has objective auditory deficits. Speech-in-noise performance was related to a combination of auditory and nonauditory factors, confirming the important role of audiology in MTBI rehabilitation. Further research is needed to evaluate the prevalence and causal relationship of auditory deficits following MTBI.

The consonant-weighted envelope difference index (cEDI): a proposed technique for quantifying envelope distortion.

PURPOSE: The benefits of amplitude compression in hearing aids may be limited by distortion resulting from rapid gain adjustment. To evaluate this, it is convenient to quantify distortion by using a metric that is sensitive to the changes in the processed signal that decrease consonant recognition, such as the Envelope Difference Index (EDI; Fortune, Woodruff, & Preves, 1994). However, the EDI relies on the entire duration of the signal, including portions irrelevant to consonant recognition. METHOD: This note describes a computationally efficient method of automatically segmenting speech in time according to the syllable structure. Our technique uses the 1st derivative of the envelope as a basis. Peaks located in the derivative were used to generate a weighting function for the computation of a metric of signal distortion. RESULTS: The weighting function significantly improved the variance explained in consonant recognition scores over previous methods. However, only 3.2% of the variance was explained in the revised model. CONCLUSION: This technique was effective in focusing the analysis of distortion on specific segments of the signal. Use of the technique has implications for speech analysis. The difference in the amplitude envelope of consonants is not a robust model of the effect of hearing aid compression on consonant recognition.